frontend: repost 'STM' blog

Author: gyuho

frontend/app/app.routing.ts

@@ -24,6 +24,7 @@ import { versions_tip_Component } from './doc/tip/versions.component';
 import { BlogComponent } from './blog/blog.component';
 import { AnnouncingEtcdV31Component } from './blog/2016/announcing-etcd-v3.1.component';
 import { AnnouncingEtcdWebsiteComponent } from './blog/2016/announcing-etcd-website.component';
+import { STMComponent } from './blog/2016/stm.component';
 
 /*
 /play
@@ -67,6 +68,7 @@ const appRoutes: Routes = [
                 children: [
                     { path: 'announcing-etcd-v31', component: AnnouncingEtcdV31Component },
                     { path: 'announcing-etcd-website', component: AnnouncingEtcdWebsiteComponent },
+                    { path: 'etcd-stm', component: STMComponent },
                 ],
             }
         ],
@@ -102,6 +104,7 @@ export const routedComponents = [
     BlogComponent,
     AnnouncingEtcdV31Component,
     AnnouncingEtcdWebsiteComponent,
+    STMComponent,
 
     PlayComponent,
 

frontend/app/blog/2016/announcing-etcd-v3.1.component.html

@@ -20,8 +20,8 @@
     <div class="blog-group">
         <router-outlet></router-outlet>
         <h2 class="blog-title">Announcing etcd v3.1</h2>
-        <time class="blog-date" datetime="2016-10-01 00:00">1 October 2016</time>
-        <p class="blog-author">By etcd team</p>
+        <time class="blog-date" datetime="2016-10-15 00:00">15 October 2016</time>
+        <p class="blog-author">By <a href="https://github.com/coreos/etcd" target="_blank" class="blog-author-link">etcd team</a></p>
 
         <br>
         <article class="blog-contents">

frontend/app/blog/2016/announcing-etcd-website.component.html

@@ -21,7 +21,7 @@
         <router-outlet></router-outlet>
         <h2 class="blog-title">Announcing etcd website</h2>
         <time class="blog-date" datetime="2016-10-01 00:00">1 October 2016</time>
-        <p class="blog-author">By etcd team</p>
+        <p class="blog-author">By <a href="https://github.com/coreos/etcd" target="_blank" class="blog-author-link">etcd team</a></p>
 
         <br>
         <article class="blog-contents">

frontend/app/blog/2016/stm-image/diagram1.png

@@ -0,0 +1,177 @@
+import { Component } from '@angular/core';
+import { BlogComponent } from '../blog.component';
+
+@Component({
+    selector: 'stm',
+    templateUrl: 'stm.component.html',
+})
+export class STMComponent extends BlogComponent {
+    constructor() {
+        super();
+    }
+
+    getCode1() {
+        return `import (
+    "fmt"
+    "encoding/binary"
+    v3 "github.com/coreos/etcd/clientv3"
+)
+
+func toUInt64(v []byte) uint64 { x, _ := binary.UVarint(v); return x }
+func fromUInt64(v uint64) []byte {
+    b := make([]byte, binary.MaxVarintLen64);
+    return b[:binary.PutUvarint(b, v)]
+}
+
+func nosyncXfer(etcd *v3.Client, from, to string, amount uint) (err error) {
+    var fromKV, toKV *v3.GetResponse
+    if fromKV, err = b.etcd.Get(context.TODO(), from); err != nil {
+        return err
+    }
+    if toKV, err = b.etcd.Get(context.TODO(), to); err != nil {
+        return err
+    }
+    fromV, toV := toUInt64(fromKV.Value), toUint64(toKV.Value)
+    if fromV < amount {
+        return fmt.Errorf("insufficient value")
+    }
+    if _, err = b.etcd.Put(context.TODO(), to, fromUInt64(toV + amount)); err != nil {
+        return err
+    }
+    _, err = b.etcd.Put(context.TODO(), from, fromUInt64(fromV - amount))
+    return err
+}
+`;
+    }
+
+    getCode2() {
+        return `func txnXfer(etcd *v3.Client, from, to string, amount uint) (error) {
+    for {
+        if ok, err := doTxnXfer(etcd, from, to amount); err != nil {
+            return err
+        } else if ok {
+            return nil
+        }
+    }
+}
+
+func doTxnXfer(etcd *v3.Client, from, to string, amount uint) (bool, error) {
+    getresp, err := etcd.Txn(ctx.TODO()).Then(OpGet(from), OpGet(to)).Commit()
+    if err != nil {
+         return false, err
+    }
+    fromKV := getresp.Responses[0].GetRangeResponse().Kvs[0]
+    toKV := getresp.Responses[1].GetRangeResponse().Kvs[1]
+    fromV, toV := toUInt64(fromKV.Value), toUint64(toKV.Value)
+    if fromV < amount {
+        return false, fmt.Errorf(“insufficient value”)
+    }
+    txn := etcd.Txn(ctx.TODO()).If(
+        v3.Compare(v3.ModRevision(from), “=”, fromKV.ModRevision),
+        v3.Compare(v3.ModRevision(to), “=”, toKV.ModRevision))
+    txn = txn.Then(
+        OpPut(from, fromUint64(fromV - amount)),
+        OpPut(to, fromUint64(toV - amount))
+    putresp, err := txn.Commit()
+    if err != nil {
+        return false, err
+    }
+    return putresp.Succeeded, nil
+}
+`;
+    }
+
+    getCode3() {
+        return `{a:2,b:2}`;
+    }
+
+    getCode4() {
+        return `import conc “github.com/coreos/etcd/clientv3/concurrency”
+func stmXfer(e *v3.Client, from, to string, amount uint) error {
+    return <-conc.NewSTMRepeatable(context.TODO(), e, func(s *conc.STM) error {
+        fromV := toUInt64(s.Get(from))
+        toV := toUInt64(s.Get(to))
+        if fromV < amount {
+            return fmt.Errorf(“insufficient value”)
+        }
+        s.Put(to, fromUInt64(toV + amount))
+        s.Put(from, fromUInt64(fromV - amount))
+        return nil
+    })
+}
+`;
+    }
+
+    getCode5() {
+        return `func NewSTM(ctx context.Context, c *v3.Client, apply func(*STM) error) <-chan error {
+    errc := make(chan error, 1)
+    go func() {
+        defer func() {
+            if r := recover(); r != nil {
+                e, ok := r.(stmError)
+                if !ok { panic(r) }
+                errc <- e.err
+            }
+        }()
+        var err error
+        for {
+            s := &STM{c, ctx, make(map[string]*v3.GetResponse), make(map[string]string)}
+            if err = apply(s); err != nil { break }
+            if s.commit() { break }
+        }
+    }()
+    return errc
+}
+`;
+    }
+
+    getCode6() {
+        return `type STM struct {
+   c *v3.Client
+   ctx context.Context
+   rset map[string]*v3.GetResponse
+   wset map[string]string
+}
+`;
+    }
+
+    getCode7() {
+        return `type stmError struct { err error}
+
+func (s *STM) Get(key string) string {
+    if wv, ok := s.wset[key]; ok {
+       return wv
+    }
+    if rv, ok := s.rset[key]; ok {
+        return string(rv.Kvs[0].Value)
+    }
+    rk, err := s.c.Get(s.ctx, key, v3.WithSerializable())
+    if err != nil {
+        panic(err)
+    }
+    s.rset[key] = rk
+    return string(rk.Kvs[0].Value)
+}
+
+func (s *STM) Put(key, val string) { s.wset[key] = val }
+`;
+    }
+
+    getCode8() {
+        return `func (s *STM) commit() bool {
+    cs := make([]v3.Cmp, 0, len(s.rset))
+    for k, rk := range s.rset {
+        cs = append(cs, v3.Compare(v3.ModRevision(k), “=”, rk.Kvs[0].ModRevision))
+    }
+    puts := make([]v3.Op, 0, len(s.wset))
+    for k, v := range s.wset {
+        puts = append(puts, v3.OpPut(k, v))
+    }
+    txnresp, err := s.c.Txn(s.ctx).If(cs…).Then(puts…).Commit()
+    if err != nil {
+        panic(err)
+    }
+    return txnresp.Succeeded
+}`;
+    }
+}

frontend/app/blog/2016/stm-image/diagram2.png

@@ -15,16 +15,12 @@ md-sidenav-layout {
     min-width: 150px;
 }
 
-a {
-    color: black;
-    text-decoration: none !important;
-}
-
 .blog-item-title-sidebar {
     color: black;
     text-decoration: none !important;
-    font-family: 'Inconsolata', monospace;
-    font-size: 14px;
+    font-family: 'Open Sans', sans-serif;
+    font-size: 13px;
+    padding-bottom: 3px;
 }
 
 .blog-title {
@@ -45,8 +41,50 @@ a {
     font-style: italic;
 }
 
+.blog-author-link {
+    color: darkgray;
+    font-family: 'Open Sans', sans-serif;
+    font-size: 13px;
+    font-style: italic;
+    text-decoration: none !important;
+}
+
 .blog-contents p {
     color: black;
-    font-family: 'Inconsolata', monospace;
-    font-size: 15px;
+    font-family: 'Open Sans', sans-serif;
+    font-size: 16px;
+    font-weight: 300;
+    font-style: normal;
+}
+
+.normal-link {
+    color: dodgerblue;
+    text-decoration: none !important;
+    font-family: 'Open Sans', sans-serif;
+    font-size: 16px;
+    font-weight: 300;
+    font-style: normal;
+}
+
+.code-light-snippet {
+    background: #f5f5f5;
+    color: #366354;
+    font-family: monospace;
+    font-size: 14px;
+}
+
+.code-light {
+    white-space: pre-wrap;
+    border-style: solid;
+    border-width: 1px;
+    border-color: lightslategrey;
+    border-radius: 5px;
+    background: #f5f5f5;
+    color: #366354;
+    font-family: monospace;
+    font-size: 14px;
+    font-weight: 400;
+    padding: 8px;
+    margin: 1em 0px 1em;
+    word-wrap: normal;
 }

frontend/app/blog/2016/stm-image/diagram3.png

@@ -41,7 +41,11 @@ export class BlogComponent {
                     new blogItem(
                         'Announcing etcd website',
                         '/blog/2016/announcing-etcd-website'
-                    )
+                    ),
+                    new blogItem(
+                        'Serializability and Distributed Software Transactional Memory with etcd3',
+                        '/blog/2016/etcd-stm'
+                    ),
                 ]
             ),
         ];

frontend/app/blog/2016/stm-image/stm-retry.png

@@ -44,20 +44,20 @@ a {
 
 sup {
     color: black;
-    font-family: 'Inconsolata', sans-serif;
+    font-family: 'Open Sans', sans-serif;
     font-size: 10px;
 }
 
 footer {
     color: black;
-    font-family: 'Inconsolata', sans-serif;
+    font-family: 'Open Sans', sans-serif;
     font-size: 12px;
 }
 
 .footer-link {
     color: dodgerblue;
     text-decoration: none !important;
-    font-family: 'Inconsolata', sans-serif;
+    font-family: 'Open Sans', sans-serif;
     font-size: 12px;
 }
 

frontend/app/blog/2016/stm-image/stm.png

@@ -81,7 +81,7 @@ <h2><a href="/doc/{{version.etcdVersionURL}}/why#when-not-to-use">When Not to Us
                 <p>
                     etcd is designed for storing small chunks of data: configuration file, JSON, YAML, etc. etcd limits the size of one request in 1.5MB (see <a href="https://github.com/coreos/etcd/blob/master/etcdserver/v3_server.go#L34-L38" target="_blank"
                         class="code-link">maxRequestBytes</a>). And default storage size limit is 2GB (see <a href="https://github.com/coreos/etcd/blob/master/mvcc/backend/backend.go#L46-L53" target="_blank" class="code-link">DefaultQuotaBytes</a>). These
-                    are the tradeoffs required for strong consistency. So if you need higher availability or bigger storage size, etcd might not be the option.
+                    are the tradeoffs that etcd makes for strong consistency. So if you need higher availability or bigger storage size, etcd might not be the option.
                 </p>
 
                 <br><br>

frontend/app/blog/2016/stm.component.html

@@ -7,10 +7,10 @@
     <base href="/">
 
     <meta name="viewport" content="width=device-width, initial-scale=1">
-    <link rel='shortcut icon' type='image/x-icon' href='https://storage.googleapis.com/etcd-play/favicon.ico' />
+    <link rel='shortcut icon' type='image/x-icon' href='/favicon.ico' />
 
     <link href="https://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet">
-    <link href="https://fonts.googleapis.com/css?family=Inconsolata|Open+Sans|Roboto" rel="stylesheet">
+    <link href="https://fonts.googleapis.com/css?family=Open+Sans|Roboto" rel="stylesheet">
 </head>
 
 <body>